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SubjectRe: [PATCH] drm: omapdrm: Do not use helper unininitialized in omap_fbdev_init()
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Added to drm-misc-next-fixes.

Am 24.02.23 um 18:25 schrieb Nathan Chancellor:
> Clang warns (or errors with CONFIG_WERROR):
>
> ../drivers/gpu/drm/omapdrm/omap_fbdev.c:235:6: error: variable 'helper' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
> if (!fbdev)
> ^~~~~~
> ../drivers/gpu/drm/omapdrm/omap_fbdev.c:259:26: note: uninitialized use occurs here
> drm_fb_helper_unprepare(helper);
> ^~~~~~
> ../drivers/gpu/drm/omapdrm/omap_fbdev.c:235:2: note: remove the 'if' if its condition is always false
> if (!fbdev)
> ^~~~~~~~~~~
> ../drivers/gpu/drm/omapdrm/omap_fbdev.c:228:30: note: initialize the variable 'helper' to silence this warning
> struct drm_fb_helper *helper;
> ^
> = NULL
> 1 error generated.
>
> Return early, as there is nothing for the function to do if memory
> cannot be allocated. There is no point in adding another label to just
> emit the warning at the end of the function in this case, as memory
> allocation failures are already logged.
>
> Fixes: 3fb1f62f80a1 ("drm/fb-helper: Remove drm_fb_helper_unprepare() from drm_fb_helper_fini()")
> Link: https://github.com/ClangBuiltLinux/linux/issues/1809
> Link: https://lore.kernel.org/oe-kbuild-all/202302250058.fYTe9aTP-lkp@intel.com/
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> ---
> This is currently showing in mainline so I believe this should go to
> drm-misc-next-fixes.
> ---
> drivers/gpu/drm/omapdrm/omap_fbdev.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/omapdrm/omap_fbdev.c b/drivers/gpu/drm/omapdrm/omap_fbdev.c
> index 84429728347f..a6c8542087ec 100644
> --- a/drivers/gpu/drm/omapdrm/omap_fbdev.c
> +++ b/drivers/gpu/drm/omapdrm/omap_fbdev.c
> @@ -233,7 +233,7 @@ void omap_fbdev_init(struct drm_device *dev)
>
> fbdev = kzalloc(sizeof(*fbdev), GFP_KERNEL);
> if (!fbdev)
> - goto fail;
> + return;
>
> INIT_WORK(&fbdev->work, pan_worker);
>
>
> ---
> base-commit: e034b8a18d4badceecb672c58b488bad1e901d95
> change-id: 20230224-omapdrm-wsometimes-uninitialized-0125f7692fbb
>
> Best regards,

--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
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